All Muscles — Origin · Insertion · Function · Innervation
Every muscle from the five lectures (Intro to Locomotor, Back/Upper Limb, Lower Limb, Abdomen/Thorax, Head-Face/Neck) in one table. Type a muscle name, bone, or nerve in the search box to filter instantly.
How to use: Columns are Origin → Insertion → Function → Innervation. The innervation column (red) is the most frequently tested — cover it first, guess, then reveal. Where origins/insertions were not given in the slides (especially facial-expression and abdominal muscles), standard anatomical references have been added; if your exam is slide-focused, prioritise function and innervation.
BACK MUSCLES
| Muscle | Origin | Insertion | Function | Innervation |
|---|---|---|---|---|
| Trapezius | Occipital bone + spinous processes of thoracic vertebrae | Clavicle, acromion, spine of scapula | Elevates/retracts scapula; aids abduction above 90° | Accessory nerve (CN XI) |
| Latissimus dorsi | Thoracic & lumbar spinous processes, iliac crest, lower ribs | Humerus (intertubercular groove) | Extension + adduction + medial rotation of humerus; aids inspiration | Thoracodorsal nerve |
| Levator scapulae | Transverse processes of C1–C4 | Medial border of scapula (upper) | Elevates the scapula | Dorsal scapular nerve |
| Rhomboid minor | Spinous processes C7–T1 | Medial border of scapula (at spine) | Retracts the scapula | Dorsal scapular nerve |
| Rhomboid major | Spinous processes T2–T5 | Medial border of scapula (lower) | Retracts the scapula | Dorsal scapular nerve |
| Serratus posterior superior/inferior | Spinous processes (cervicothoracic / thoracolumbar) | Upper / lower ribs | Aid respiration (elevate/depress ribs) | Intercostal nerves |
| Splenius capitis/cervicis | Nuchal ligament, upper thoracic spinous processes | Mastoid process / upper cervical transverse processes | Head/neck extension, ipsilateral rotation | Dorsal rami of spinal nerves |
| Erector spinae (iliocostalis-longissimus-spinalis) | Sacrum, iliac crest, lumbar spinous processes | Ribs, transverse processes, spinous processes, mastoid | Extension of vertebral column, posture | Dorsal rami of spinal nerves |
| Semispinalis / multifidus / rotatores (deep) | Transverse processes | Spinous processes (higher levels) | Extension, rotation, posture | Dorsal rami of spinal nerves |
UPPER LIMB
| Muscle | Origin | Insertion | Function | Innervation |
|---|---|---|---|---|
| Pectoralis major | Clavicle & sternum | Humerus (lateral lip of intertubercular groove) | Arm adduction + medial rotation (clavicular head flexes); forms anterior axillary fold | Medial & lateral pectoral nerves |
| Pectoralis minor | Ribs 3–5 | Scapula (coracoid process) | Pulls scapula down/forward, stabilises it; aids inspiration | Medial pectoral nerve |
| Serratus anterior | Lateral surface of ribs 1–8 | Medial border of scapula (anterior surface) | Protracts/stabilises scapula | Long thoracic nerve |
| Deltoid | Clavicle, acromion, spine of scapula | Humerus (deltoid tuberosity) | Flexion+medial rot. / abduction / extension+lateral rot. | Axillary nerve |
| Supraspinatus (rotator cuff) | Supraspinous fossa | Greater tubercle of humerus | Initiates abduction (NOT a rotator) | Suprascapular nerve |
| Infraspinatus (rotator cuff) | Infraspinous fossa | Greater tubercle | Lateral rotation | Suprascapular nerve |
| Teres minor (rotator cuff) | Lateral border of scapula | Greater tubercle | Lateral rotation | Axillary nerve |
| Subscapularis (rotator cuff) | Subscapular fossa | Lesser tubercle of humerus | Medial rotation | Upper & lower subscapular nerves |
| Teres major | Inferior angle of scapula | Humerus (medial lip of intertubercular groove) | Adduction, medial rotation, extension | Lower subscapular nerve |
| Biceps brachii | Scapula: long head (supraglenoid tubercle), short head (coracoid) | Radial tuberosity; bicipital aponeurosis | Primary supinator of forearm; flexes supinated forearm; aids arm flexion | Musculocutaneous nerve |
| Brachialis | Anterior humerus (distal) | Ulna (coronoid process / tuberosity) | Primary flexor of forearm | Musculocutaneous nerve |
| Coracobrachialis | Coracoid process | Mid-humerus (medial surface) | Arm flexion & adduction | Musculocutaneous nerve |
| Triceps brachii | Long head (infraglenoid tubercle), lateral & medial head (posterior humerus) | Olecranon of ulna | Chief extensor of forearm; long head aids arm ext./add. | Radial nerve |
| Forearm flexor group (general) | Mostly medial epicondyle (common flexor origin) | Hand bones (deep to flexor retinaculum) | Wrist/finger flexion, pronation | Median nerve (2 exceptions: Ulnar) |
| Forearm extensor group (general) | Mostly lateral epicondyle (common extensor origin) | Hand bones (deep to extensor retinaculum) | Wrist/finger extension, supination | Radial nerve |
| Brachioradialis | Lateral supracondylar ridge of humerus | Distal radius (near styloid) | Flexes forearm (posterior compartment but a flexor) | Radial nerve |
| Thenar muscles (abd./flex./opponens pollicis brevis) | Flexor retinaculum & carpal bones | 1st digit (pollex) phalanx/metacarpal | Thumb abduction/flexion/opposition | Median nerve |
| Hypothenar muscles (abd./flex./opp. digiti minimi) | Flexor retinaculum & carpal bones | 5th digit phalanx/metacarpal | Little finger abduction/flexion/opposition | Ulnar nerve |
| Adductor pollicis | 2nd–3rd metacarpal / capitate | Thumb proximal phalanx | Thumb adduction | Ulnar nerve |
| Lumbricals (×4) & interossei | FDP tendons / metacarpals | Extensor expansion / phalanges | MCP flexion + IP extension; finger abd/add | Lateral 2 lumbricals: Median; rest: Ulnar |
Major nerve summary: Musculocutaneous (C5-7) → anterior arm (biceps, brachialis, coracobrachialis); Axillary (C5-6) → deltoid & teres minor; Radial (C5-T1) → triceps, anconeus, brachioradialis, ECRL; Median (C6-T1) → forearm flexors + thenar; Ulnar (C8-T1) → hypothenar + adductor pollicis + interossei. Exception: Trapezius is NOT from the brachial plexus — accessory nerve (XI).
LOWER LIMB
| Muscle | Origin | Insertion | Function | Innervation |
|---|---|---|---|---|
| Gluteus maximus | Ilium, sacrum, coccyx | Iliotibial tract (lateral condyle of tibia) & femur (gluteal tuberosity) | Thigh extension & lateral rotation; aids knee extension | Inferior gluteal nerve |
| Gluteus medius | Outer surface of ilium | Greater trochanter | Thigh abduction (most powerful) & medial rotation | Superior gluteal nerve |
| Gluteus minimus | Outer surface of ilium (lower) | Greater trochanter | Thigh abduction & medial rotation | Superior gluteal nerve |
| Tensor fascia lata | Iliac crest / ASIS | Iliotibial tract | Thigh flexion/abduction; tenses ITT | Superior gluteal nerve |
| Piriformis · Obturator internus · Gemelli · Quadratus femoris | Sacrum / pelvis (around foramina) | Greater trochanter / intertrochanteric crest | Lateral rotation of thigh | Direct branches of sacral plexus |
| Iliacus | Iliac fossa | Lesser trochanter | Thigh flexion (iliopsoas) | Femoral nerve |
| Psoas major | T12–L5 bodies/transverse processes & IV discs | Lesser trochanter | Thigh flexion; posture; trunk flexion | Lumbar plexus (L1-3) direct branches |
| Quadratus lumborum | Iliac crest | 12th rib & L1-4 transverse processes | Lateral flexion; fixes 12th rib | T12 & upper lumbar nerves |
| Sartorius | ASIS | Medial tibia (pes anserinus) | Thigh flexion+abd.+lat. rot.; knee flexion (longest muscle) | Femoral nerve |
| Quadriceps femoris (rectus femoris + 3 vastus) | Rectus femoris: AIIS; vasti: femur | Patella → patellar lig. → tibial tuberosity | Knee extension; rectus femoris flexes thigh | Femoral nerve |
| Pectineus | Pubis (pecten pubis) | Femur (pectineal line) | Thigh adduction & flexion | Femoral nerve (sometimes obturator) |
| Adductor longus | Pubis (body) | Linea aspera | Thigh adduction | Obturator nerve |
| Adductor brevis | Pubis (inferior ramus) | Linea aspera (upper) | Thigh adduction | Obturator nerve |
| Adductor magnus | Adductor part: pubis & ischium · Hamstring part: ischial tuberosity | Adductor part: linea aspera · Hamstring part: adductor tubercle | Add.+flexion / Add.+extension | Adductor part: Obturator · Hamstring part: Tibial |
| Gracilis | Pubis (inferior ramus) | Medial tibia (pes anserinus) | Thigh adduction; knee flexion | Obturator nerve |
| Semitendinosus (hamstring) | Ischial tuberosity | Medial surface of tibia (upper) | Leg flexion + medial rotation; thigh extension | Tibial nerve |
| Semimembranosus (hamstring) | Ischial tuberosity | Posterior part of medial condyle | Leg flexion + medial rotation; thigh extension | Tibial nerve |
| Biceps femoris (hamstring) | Long head: ischial tuberosity · Short head: linea aspera | Fibula (head) | Leg flexion + lateral rotation; thigh extension | Long head: Tibial · Short head: Common peroneal |
| Anterior leg (tibialis ant., EDL, EHL, peroneus tertius) | Anterior tibia/fibula, interosseous membrane | Foot/toe bones (dorsum) | Dorsiflexion, toe extension | Deep peroneal nerve |
| Lateral leg (peroneus longus & brevis) | Lateral surface of fibula | 1st metatarsal/medial cuneiform · 5th metatarsal | Eversion, aids plantar flexion | Superficial peroneal nerve |
| Gastrocnemius (superficial posterior) | Medial & lateral condyle of femur | Calcaneus (Achilles/calcaneal tendon) | Plantar flexion (when leg extended), leg flexion | Tibial nerve |
| Soleus & Plantaris (superficial posterior) | Fibula/tibia (soleal line); femur lateral condyle | Calcaneus (Achilles tendon) | Plantar flexion | Tibial nerve |
| Deep posterior leg (popliteus, FHL, FDL, tibialis post.) | Posterior tibia/fibula, interosseous membrane | Foot/toe bones (plantar) | Plantar flexion, toe flexion, inversion | Tibial nerve |
| Foot dorsum muscles (ext. digitorum/hallucis brevis) | Calcaneus (dorsal) | Toe extensor tendons | Toe extension | Deep peroneal nerve |
| Foot sole muscles (4 layers) | Calcaneus, plantar aponeurosis, tendons | Toe phalanges | Maintain arch, toe movements | Medial & lateral plantar nerve (Tibial branches) |
Dual-innervation exceptions: Adductor magnus (Obturator + Tibial) and Biceps femoris (Tibial + Common peroneal). Femoral n. → anterior thigh; Obturator n. → medial thigh; Tibial n. → posterior thigh + posterior leg + sole; Peroneal → anterior/lateral leg + foot dorsum.
ABDOMEN, THORAX & DIAPHRAGM
| Muscle | Origin | Insertion | Function | Innervation |
|---|---|---|---|---|
| External abdominal oblique | Outer surface of ribs 5–12 | Linea alba, iliac crest, pubic tubercle (aponeurosis) | Trunk flexion/lateral flexion; rotation to the opposite side | T7–T12 (+ iliohypogastric) |
| Internal abdominal oblique | Thoracolumbar fascia, iliac crest, inguinal lig. | Lower ribs, linea alba, pubis | Trunk flexion/lateral flexion; rotation to the same side | T7–T12, L1 |
| Transversus abdominis | Lower ribs, thoracolumbar fascia, iliac crest, inguinal lig. | Linea alba, pubis (aponeurosis) | Increases intra-abdominal pressure; supports viscera | T7–T12, L1 |
| Rectus abdominis | Pubic crest & symphysis | Xiphoid process & costal cartilages 5–7 | Trunk flexion; intra-abdominal pressure | T7–T12 (ventral rami) |
| Pyramidalis | Pubis | Linea alba | Tenses the linea alba | Subcostal nerve (T12) |
| Psoas minor (posterior wall) | T12–L1 bodies | Pectineal line / iliopubic eminence | Weak trunk flexion | Lumbar plexus (L1) |
| External intercostal (11 pairs) | Lower border of rib | Upper border of rib below | Elevates ribs → primary inspiration (with diaphragm) | Intercostal nerves |
| Internal & innermost intercostal | Upper border of rib (inner) | Lower border of rib above | Depresses ribs → expiration | Intercostal nerves |
| Subcostal | Inner surface of ribs (posterior) | 1–2 ribs below | Aids expiration | Intercostal nerves |
| Levator costarum (12 pairs) | Transverse processes C7–T11 | Rib below | Aids inspiration | Dorsal rami (cervicothoracic) |
| Transversus thoracis | Inner surface of sternum & xiphoid | Costal cartilages 2–6 | Aids expiration | Intercostal nerves |
| Diaphragm | Xiphoid, lower 6 ribs, lumbar crura (L1-L3) | Central tendon | Main muscle of inspiration; increases vertical dimension of thorax | Phrenic nerve (C3-4-5) |
Diaphragm openings: T8 = IVC (+ right phrenic); T10 = oesophagus (+ vagus); T12 = aorta (+ thoracic duct + azygos). General innervation of abdominal muscles: T7–T12 + L1 (iliohypogastric & ilioinguinal).
HEAD-FACE & NECK
A) Muscles of Mastication — all CN V3
| Muscle | Origin | Insertion | Function | Innervation |
|---|---|---|---|---|
| Masseter | Maxillary process of zygomatic bone & zygomatic arch | Outer surface of ramus & coronoid process | Mandible elevation + protrusion; occlusion | Mandibular n. (V3) – masseteric n. |
| Temporalis | Temporal fossa & temporal fascia | Coronoid process & ramus | Mandible elevation + retraction; occlusion | Mandibular n. (V3) – deep temporal n. |
| Medial pterygoid | Sup.: tuberosity of maxilla + pyramidal process of palatine · Deep: medial surface of lateral pterygoid plate | Medial surface of ramus & angle | Elevation + protrusion | Mandibular n. (V3) – medial pterygoid n. |
| Lateral pterygoid | Sup. head: greater wing of sphenoid · Inf. head: lateral surface of lateral pterygoid plate | Sup.: TMJ capsule · Inf.: neck of condyle | Depression (opens mouth), protrusion, side movement | Mandibular n. (V3) – lateral pterygoid n. |
B) Muscles of Facial Expression — all CN VII
| Muscle | Origin (standard) | Insertion | Function / Expression | Innervation |
|---|---|---|---|---|
| Epicranius (occipitofrontalis) | Galea aponeurotica / occipital bone | Skin of forehead / eyebrow | Frontal: raises eyebrows (surprise); occipital: retracts scalp | Facial n. (VII) |
| Orbicularis oris | Around maxilla/mandible, lip skin | Skin/mucosa of lips | Closes/narrows mouth; speech, chewing, sucking, whistling | Facial n. (VII) |
| Orbicularis oculi | Medial palpebral lig., orbital margin | Eyelid / lateral raphe | Closes the eyelid; drains lacrimal punctum | Facial n. (VII) |
| Buccinator | Alveolar processes of maxilla/mandible, pterygomandibular raphe | Angle of mouth (orbicularis oris) | Deepest facial muscle; presses cheek to teeth, aids chewing, blowing | Facial n. (VII) |
| Zygomaticus major/minor | Zygomatic bone | Angle of mouth | Elevates angle of mouth superolaterally — smiling | Facial n. (VII) |
| Levator labii superioris (± alaeque nasi) | Maxilla / frontal process | Upper lip / nostril | Elevates the upper lip | Facial n. (VII) |
| Levator anguli oris | Maxilla (canine fossa) | Angle of mouth | Elevates angle of mouth; nasolabial fold | Facial n. (VII) |
| Depressor labii inferioris | Mandible (oblique line) | Lower lip | Pulls lower lip down — sadness | Facial n. (VII) |
| Depressor anguli oris | Mandible (oblique line) | Angle of mouth | Pulls angle of mouth down — sadness | Facial n. (VII) |
| Mentalis | Mandible (incisive fossa) | Skin of chin | Raises chin skin — doubt | Facial n. (VII) |
| Risorius (Santorini) | Parotid/masseteric fascia | Angle of mouth | Pulls angle of mouth laterally | Facial n. (VII) |
| Procerus | Nasal bone | Skin of glabella | Draws eyebrows down, transverse wrinkles — frowning | Facial n. (VII) |
| Corrugator / Depressor supercilii | Frontal bone (supraorbital) | Skin of eyebrow | Approximates/vertically wrinkles eyebrows | Facial n. (VII) |
| Nasalis / Depressor septi | Maxilla | Nasal cartilage/septum | Narrows/widens the nostril | Facial n. (VII) |
| Platysma | Pectoral/deltoid fascia (upper chest skin) | Lower border of mandible, angle of mouth, cheek skin | Aids opening mouth, tenses neck skin — fear | Facial n. (VII) – cervical branch |
C) Suboccipital Muscles — all suboccipital n. (C1)
| Muscle | Origin | Insertion | Function | Innervation |
|---|---|---|---|---|
| Rectus capitis posterior major | Spinous process of axis (C2) | Inferior nuchal line | Extension + ipsilateral rotation | Suboccipital n. (C1 dorsal ramus) |
| Rectus capitis posterior minor | Posterior tubercle of atlas (C1) | Inferior nuchal line | Extension | Suboccipital n. (C1) |
| Obliquus capitis inferior | Spinous process of axis (C2) | Transverse process of atlas | Ipsilateral rotation | Suboccipital n. (C1) |
| Obliquus capitis superior | Transverse process of atlas | Inferior nuchal line | Lateral flexion, aids extension | Suboccipital n. (C1) |
D) Suprahyoid & Infrahyoid Muscles
| Muscle | Origin | Insertion | Function | Innervation |
|---|---|---|---|---|
| Mylohyoid (suprahyoid) | Mylohyoid line of mandible | Hyoid bone | Elevates floor of mouth/tongue/hyoid (forms floor of mouth) | Mandibular n. (V3) |
| Geniohyoid (suprahyoid) | Inner surface of mandible | Hyoid bone | Elevates hyoid antero-superiorly | Anterior ramus of C1 |
| Digastric (suprahyoid) | Ant. belly: mandible · Post. belly: temporal bone | Hyoid bone | Depresses mandible, raises hyoid | Ant. belly: V3 · Post. belly: VII |
| Stylohyoid (suprahyoid) | Styloid process | Hyoid bone | Elevates hyoid postero-superiorly | Facial n. (VII) |
| Sternohyoid (infrahyoid) | Manubrium of sternum | Hyoid bone | Depresses hyoid | Ansa cervicalis |
| Sternothyroid (infrahyoid) | Manubrium of sternum | Thyroid cartilage | Depresses hyoid/larynx | Ansa cervicalis |
| Thyrohyoid (infrahyoid) | Thyroid cartilage | Hyoid bone | Depresses hyoid, elevates larynx | Anterior ramus of C1 |
| Omohyoid (infrahyoid) | Sup. belly: hyoid · Inf. belly: superior border of scapula | Clavicle | Depresses hyoid | Ansa cervicalis |
E) Neck Muscles (Superficial, Scalene, Prevertebral)
| Muscle | Origin | Insertion | Function | Innervation |
|---|---|---|---|---|
| Sternocleidomastoid (SCM) | Sternal head: manubrium · Clavicular head: medial 1/3 of clavicle | Mastoid process | Unilateral: bends head/turns face to opposite side · Bilateral: neck flexion | Accessory n. (CN XI) |
| Anterior scalene | Cervical transverse processes | 1st rib | Elevates 1st rib; flexes/laterally rotates neck | Cervical spinal nerves (ventral rami) |
| Middle scalene | Cervical transverse processes | 1st rib | Elevates 1st rib; bends neck laterally | Cervical spinal nerves |
| Posterior scalene | Cervical transverse processes | 2nd rib | Elevates 2nd rib; bends neck laterally | Cervical spinal nerves |
| Longus capitis (prevertebral) | Cervical transverse processes | Occipital bone | Flexes the head | Cervical spinal nerves |
| Longus colli (prevertebral) | C3–T3 bodies/transverse processes | Atlas / upper cervical vertebrae | Neck flexion (C2-C7); unilateral rotation to opposite side | Cervical spinal nerves |
| Rectus capitis anterior (prevertebral) | Atlas (C1) | Occipital bone | Flexes the head | C1–C2 ventral rami |
| Rectus capitis lateralis (prevertebral) | Atlas (C1) | Occipital bone | Laterally flexes the head | C1–C2 ventral rami |
Neck innervation golden rules: SCM + Trapezius → CN XI; all facial-expression muscles → CN VII; all muscles of mastication → CN V3; the four suboccipitals → C1 (suboccipital n.); infrahyoids → ansa cervicalis (except thyrohyoid → C1); diaphragm → phrenic (C3-5). Two-belly exception: digastric (V3 + VII).
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